Thomas Edison was known for his wacky publicity stunts, but during the Christmas of 1880 he went for the sentimental rather than shock value. That year, instead of electrocuting an elephant, he brought us the first electric Christmas light display.

Two years later, an Edison crony named Edward Johnson displayed the first electrically illuminated Christmas tree at his home in Manhattan. The then-impressive 80-light display girded a very unimpressive Charlie Brown Christmas tree (I mean really, look at that thing). And as you might expect, Johnson's feat was also intended as an advertising tool [PDF].

The tradition of stringing electric lights may have started as a Christmas thing in America, but now it's a global phenomenon used for all kinds winter festivuses (festivi?). It's a practice we take for granted—come December, they're everywhere. The evolution of the Christmas light parallels that of the light bulb, with some remarkably ornate—OK, tacky—variations. But regardless of how they look, one thing's for certain: They're a much better option than sticking a candle in a tree.

In the Beginning, There was Fire

Today we look at Christmas lights and think "Oh, those are pretty." But the tradition of lighting lights in the winter months didn't start off with aesthetics in mind. December is the darkest month of the year with the shortest days. People living without central heating in the 12th century were understandably unhappy when the sun went down and plunged them into the cold depths of night. Brian Murray's article tells us that back during the winter of 1184 was the first recorded lighting of the Yule Log [PDF] in Germany. The burning log was seen as a symbol of the sun's promise to return. It probably didn't hurt that a big burning hunk of wood makes for a pretty good heat source.

The Christmas tree has a whole story behind it that we won't get into here, but if you want to know more check out this guide. (Fun Fact: they were originally hung upside down from the ceiling—hilarious!) Long story short, Christians had lights, they had trees, and in the 17th century, they decided to put the two together.

Unfortunately, the only way to add Christmas lights to a tree back then was with candles. Obviously, this was a pretty bad idea. So bad that, unlike today, the tree would only be put up a few days before Christmas [PDF] and was promptly taken down afterwards. Murray's article describes how the candles would remain lit only for a few minutes per night, and even then families would sit around the tree and watch it vigilantly, buckets of sand and water nearby. It's kind of like the old-timey equivalent of deep-frying a turkey: People knew it could burn their house down, but proceeded to do it anyway.

By 1908, insurance companies wouldn't even pay for damages [PDF] caused by Christmas tree fires. Their exhaustive research demonstrated that burning wax candles that were loosely secured to a dried-out tree inside your house wasn't safe. At all. Electric Christmas lights were becoming a viable option for some Americans. They weren't perfect—incandescent bulbs can get plenty hot, and sparks from malfunctioning strings can still light up a dry tree—but it was a much safer option than lighting multiple fires so close to their favorite fuel.

Keep in mind that by "some Americans," I mean the extremely rich. In 1900, a single string of electric lights cost $12 [PDF]—around $300 in today's money. It would take the magic of mass manufacturing to create the Clark Griswold-esque neighborhood light displays would become an American tradition.

The Dawn of Tacky Lights

In 1900, eight years after General Electric purchased the patent rights to Edison's bulbs, the first known advertisement for Christmas tree lights appeared in Scientific American Magazine. Like I said, these suckers weren't cheap. They were so expensive that the ad suggests renting lights for a holiday display.

Twenty-five years later, demand was up. There were 15 companies in the biz of selling Christmas lights, and in 1925 they formed a consortium called the NOMA Electric Corporation, the largest Christmas light manufacturer in the world.

Even though NOMA was formed three years prior to the Great Depression, their appeal was great enough to pull through, becoming a juggernaut that was synonymous with Christmas lights from the Depression clear through to the Civil Rights Movement. NOMA didn't just further Edison's vision, though. They worked hard to bedazzle, becoming the world's biggest manufacturer of the bubble light—arguably the first great mass-produced tacky Christmas decoration.

Though NOMA is no more, these psychedelic bubble lights are thankfully still in existence. As JimOnLight.com describes, the colorful round plastic cases hold an unseen bulb, while a candle-shaped vial of clear liquid protrudes upward. As the bulb heats up, the liquid—usually methylene chloride, a chemical with a low boiling point—also heats up, so that the vial would bubble, flickering like the candle it was supposed to replace.

Alas, in 1968 the NOMA Electric Company stopped manufacturing lights, and the bubble lights became more of a novelty, soon to be joined by a host of ridiculously shaped Christmas lights, including chili peppers, flamingos, and the ridiculous beer can lights and a miniaturized version of that leg from A Christmas Story as seen on JimOnLight.com.

With NOMA, the tacky Pandora's box had opened, and even people who didn't spring for bubble lights or their Tex-Mex successors have done wonders with the decidedly more standardized sets we all know today. Once they were weatherproofed for outdoor use, it was only a matter of time before they were stapled to every square inch of house, hearth, tree, even truck.

The Lights You Know and Love

Incandescent lights are the ones that started it all. Even though they're well over a hundred years old now, the technology largely remains the same. The shapes and sizes of the bulbs, on the other hand, have been in constant flux. Now we're left with three major types of incandescent Christmas light bulbs, as described by the excellent guide at JimOnLight.com:

The Mini/Fairy Light: This is the big kahuna. If you haven't seen one of these by now, then you've probably never seen Christmas lights. Traditionally, the set is wired in series, hence the age old problem where if one bulb goes out, the rest won't light. But it's not hard to find sets that are wired in parallel nowadays.

These guys also have a lo-fi twinkle method built in. That little red-tipped bulb that comes with each set is made in a way that as the filament heats up, it rises and breaks the circuit. That, of course, shuts of the rest of the lights. When it cools down, it falls again to complete the circuit, and the lights (wait for it...) come back on. Physics 101.

C7: Again, an incandescent light that comes in a different-sized glass housing. These are about the size of your thumb, and work in almost exactly the same way as a mini light.

C9: You get the picture by now. Same shape as the C7, but slightly bigger.

LED lights have been growing in popularity for the past few years. Regardless of what you think of their light output, there's no denying that they're much more energy efficient than incandescent bulbs, and give off less heat. And who knows, maybe someday they'll match the color temperature of good-ol' tungsten lighting. Until then, here's what you'll be looking at, again according to the guide at JimOnLight.com:

LEDs are efficient. But by choice, my house is still bathed in the warm glow of hot electrified…
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5mm: These are the LED equivalent of incandescent mini-lights. They're small LED bulbs in a plastic enclosure. Usually the "white" level is waaaay off from the "white" of incandescent lights.

G12 and G25: Just like with incandescent lights, you're going to find a whole lot of the same with LEDs, just in different shapes and sizes. These are globe shaped plastic enclosures, G12 is pictured.

C7: You've seen these before, except this time there's an LED inside.

You'll find a bunch of crazy light designs out there, but like Jim's excellent guide says, 99.9% of them are just plastic enclosures that are illuminated by these types of bulbs.

A Long Way From Candles

The basic foundation of the Christmas light, the incandescent bulb, hardly changed for nearly a century, and is only now undergoing is first major revolution, as we we start replacing our old tungsten lights with energy-efficient LEDs. Yet, in that same time, we've gone from sticking burning candles in a tree to creating massive, computer-controlled—and completely excessive—light displays like this:

One thing's for sure: No matter what the technology at hand, no matter what the reason to celebrate, the human desire to light up trees and houses in the cold darkness of the winter months will forever be a source for amazing—and often hilarious—innovation.